Recent technologies have been used to form layers of fine fiber. Fine fiber technologies that contemplate polymeric materials mixed or blended with a variety of other substances are disclosed in, for example Chung et al., U.S. Pat. No. 6,743,273. These fibers have found commercial acceptance in certain filtration applications in which a layer of fine fiber is found on a filtration substrate. Certain of the disclosed fibers comprise an axial core comprising a phase comprising polymer materials. Surrounding the axial core can be found a layer of a coating material such as a phenolic oligomer or a fluoropolymer component. In the formation of these fibers, a solution of the polymer and additive is formed by melt processes or electrospun to form the fiber.